Changeover valve for a central air conditioning unit

ABSTRACT

A valve is provided with one inlet and two outlets with one of the outlets being normally closed by a valve in the form of a film disc carried by a flexible blade. A magnetic pad secured to the blade is attracted by the proximity of an actuator carrier magnetic element to cause the flexing of the blade to open the normally closed outlet and to close the normally open outlet. The actuator may be either thermally or electrically actuated and is suitable to override a bleed thermostat to permit warm-up of an overcooled area or to cause a switchover in operation between a heating and cooling mode by connecting the appropriate bleed thermostat so as to control the inflation of the bellows.

This application is a division of application Ser. No. 125,897, filedNov. 17, 1987, now U.S. Pat. No. 4,844,149, which is a division ofapplication Ser. No. 816,187, filed Jan. 6, 1986, pending.

BACKGROUND OF THE INVENTION

In central air conditioning systems where conditioned air is supplied ata single temperature, it is often necessary and/or desirable to changeover from heating to cooling and vice versa. Such changeovers can belong-term, as in the case of seasonal changes or short-term, as in thecase of warming up an overcooled building prior to the arrival of thework force. For example, after a weekend or holiday during which theminimum cooling condition overcooled the building in the absence of thecooling load supplied by the personnel, lights and equipment, it isdesirable to warm the building long enough to reduce the overcooling toan acceptable level. The thermostatic response is, however, correctwithout change for only one mode of operation. If, for example, thethermostatic response is correct for cooling, the supplying of heatedair will encounter a minimum or no flow condition in an undercooled zoneor area and dissatisfaction causing overheating if the zone temperatureis above the cooling set point. Obviously, neither condition issatisfactory or energy efficient.

SUMMARY OF THE INVENTION

The present invention is directed to a warm-up/changeover valve orproximity switch suitable for use in a system powered device in whichair flow into a zone is controlled by the degree of bellows inflationwhich is in turn controlled by a thermostatic bleed valve. Thewarm-up/changeover valve or proximity switch can be eitherthermostatically responsive or solenoid actuated. If the use is to befor warm-up, a bleed line for deflating the bellows is opened when thevalve is opened in response to the supplying of warm air or to theceasing of the supplying of electrical power to the solenoid as due tothe opening of a thermostatic switch. If a changeover function isrequired, the valve is configured as a valve with one outlet supplyingair to the heating thermostat and one outlet supplying air to thecooling thermostat.

It is, therefore, an object of this invention to provide athermostatically responsive valve or proximity switch for achieving awarm-up or changeover function in a conditioned air distributing system.

It is another object of this invention to provide an uncontrolledwarm-up function in which a valve bypasses a cooling only, duct poweredthermostat bleeding an inflatable bellows in a normally open unit whenwarm air reaches the sensing element controlling the valve in oneembodiment and in response to an electric signal in another embodiment.

It is a further object of this invention to provide a switchover ofcontrol air pressure to either side of a two port, heating/cooling ductpowered thermostat in response to a change in the duct temperature inone embodiment and in response to an electric signal in a secondembodiment.

It is an additional object of this invention to provide a thermostatbypass or shutoff of a duct powered control in response to an externalelectric signal as from a fire switch or interlock. These objects, andothers as will become apparent hereinafter, are provided according tothe teachings of the present invention.

Basically, a valve or proximity switch assembly is provided with aninlet, a normally open outlet and a normally closed outlet. A valveelement is movable between two positions respectively blocking one ofthe two outlets. The movement of the valve element to the positionclosing the normally open outlet, and thereby opening the normallyclosed outlet, is responsive to the movement of a magnetic member intosufficient proximity to cause the valve element to snap over from oneposition to the other. The magnetic member is carried by an actuatorwhich is moved in one embodiment responsive to a change in thetemperature of the conditioned air being supplied and in anotherembodiment responsive to an electrical signal.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the present invention, reference shouldnow be made to the following detailed description thereof taken inconjunction with the accompanying drawings wherein:

FIG. 1 is a schematic representation of a central air conditioningsystem employing the present invention for a warm-up function;

FIG. 2 is a schematic representation of a central air conditioningsystem employing the present invention for a heating/cooling changeover;

FIG. 3 is a pictorial view of a first embodiment of the presentinvention;

FIG. 4 is a sectional view taken along line 4--4 of FIG. 3 showing thevalve element in a first, actuated position;

FIG. 5 is a sectional view of a second embodiment of the presentinvention corresponding to FIG. 4 and showing the valve element in asecond, unactuated position;

FIG. 6 is a sectional view of a third embodiment of the presentinvention showing the valve element in the second position but which isthe solenoid actuated position;

FIG. 7 is a pictorial view of the valve element;

FIG. 8 is a top view of the valve element; and

FIG. 9 is a sectional view taken along line 9--9 of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates the use of the present invention in a warm-upconfiguration and is suitable for use with either actuator 150, 250 or350 which will be described in more detail hereinafter. The numeral 10generally designates an air distribution unit in which conditioned airis delivered from a central source thereof (not illustrated) to a plenumchamber 12 of the air distribution unit. A damper arrangementillustrated as inflatable bellows 14 and 15 regulates the flow ofconditioned air from the plenum 12 to the area or space beingconditioned. A portion of the conditioned air furnished to plenumchamber 12 flows through filter 20 where any foreign bodies entrainedtherein will be removed. The conditioned air passing through filter 20is used for controlling the operation of unit 10. The control air passesfrom filter 20 to pressure regulator 30 via line 22. The control airpasses from regulator 30 into distributor 40 via line 38 and fromdistributor 40 via lines 41 and 42 to bellows 14 and 15, respectively.Additionally, control air passes via line 39 to bleed-type thermostat 50which senses the temperature of the area to be conditioned and inresponse thereto controls the magnitude of the control signal suppliedto bellows 14 and 15 by bleeding control air through bleed port 52 andthe aperture 55 of apertured sliding plate 54. The common or inlet port107 of valve assembly 100 is connected upstream of bleed port 52 vialine 58. Normally open outlet 109 is capped by a cap 109a so that line58 is normally blocked and has no influence on thermostat 50. Assumingthat thermostat 50 is set for cooling an area, the slide plate 54 andtherefore the inflation of bellows 14 and 15 will be adjustedaccordingly.

If, as described above, an overcooling situation exists in the area andit is desired to have an uncontrolled warm-up, the mere supplying ofwarm air would not cause the flow of warm air into the area because theresonse of thermostat 50 to the overcooling is to inflate bellows 14 and15 to block flow into the area. Actuator 150, as illustrated, actuator250, or thermostatic switch 180 of actuator 350 is exposed to the warmair in the plenum or the flowing air stream which causes the actuationof actuator 150 (or actuator 250, or the deactuation of actuator 350)which causes the flexure of blade 122 to the FIG. 4 position due to themagnetic attraction between magnetic member 165 and magnetic pad 128. Inthis position, port 104 is uncovered so that bellows 14 and 15 areconnected to atmosphere via lines 41 and 42, distributor 40, line 38,line 39, line 58 and outlet 105 which effectively bypasses/disablesthermostat 50 such that bellows 14 and 15 deflate and warm air isdelivered to the area independent of thermostat 50.

FIG. 2 illustrates the use of the present invention in a cooling/heatingchangeover configuration and is suitable for use with actuator 150, 250or 350. The numeral 10 generally designates an air distribution unit asdescribed with respect to FIG. 1 in which conditioned air flows throughfilter 20 to pressure regulator 30 via line 22 and passes from regulator30 into distributor 40 via line 38. The air passes from distributor 40via lines 41 and 42 to bellows 14 and 15, respectively. Additionally,control air passes via line 39 to common or inlet port 107 of valveassembly 100. Normally open outlet 109 is connected to coolingthermostat 70 via line 71 and normally closed outlet 105 is connected toheating thermostat 72 via line 73. Thermostats 70 and 72 are oppositelyacting bleed thermostats such as is illustrated in FIG. 1 and designated50. They are oppositely acting in that cooling thermostat 70 controlsthe lowering of the room temperature to the set point whereas heatingthermostat 72 controls the raising of the room temperature to the setpoint.

The actuator 350, as illustrated, may have a switch 180 which may be ofa thermostatic type and exposed to the plenum air or flowing air stream,or it may be a switch controlled by a computer or the like. The actuatedand unactuated position of actuator 350 are the reverse of those ofactuators 150 and 250. In the actuated position of actuator 350, controlair passes via line 39 to port 107, through valve assembly 100, out port109 and passes via line 71 to cooling thermostat 70 which controls theinflation of bellows 14 and 15 as described above. If actuator 350 isunactuated, control air will pass via line 39 to port 107, through valveassembly 100, out port 105 and will pass via line 73 to heatingthermostat 72 which controls the inflation of bellows 14 and 15 asdescribed above. Actuator 150 or 250 would similarly respond to theplenum air or flowing air system so as to connect ports 107 and 109 inresponse to cool air and ports 107 and 105 in response to hot air butthe designation of the actuated and unactuated positions would bereversed. If desired, the ports 109 and 105 could be connected tothermostats 72 and 70, respectively, if the heating mode was desired tobe the actuated mode of actuator 350 or the unactuated mode of actuator150 or 250. Where switch 180 is computer controlled, in addition toproviding a changeover between heating and cooling, ventilation can beminimized in the case of a fire by causing the system to go over to theheating mode which would reduce the supplying of fresh air to the fire.Additionally, where valve assembly 100 is connected as shown in FIG. 1and powered by actuator 350, an electric signal actuating actuator 350will open port 105 to cause the bypassing of thermostat 50 and thedeflating of bellows 14 and 15 providing maximum air circulation whichis desired on the building floors above and below a fire. As noted, onthe fire floor itself port 105 remains closed and the raised spacetemperature will cause the bellows 14 and 15 to inflate due to thestopping of bleed flow from thermostat 50 and thereby stop the flow ofair to the space.

In FIGS. 3 and 4, the numeral 100 generally designates the valveassembly or proximity switch and the numeral 150 generally designatesthe actuator. The valve assembly 100 includes mating casing parts 102and 103 which are of a non-magnetic material, such as plastic, and areglued or otherwise suitably secured together in a fluid tight assembly.Casing part 102 defines a normally closed port 104 which is fluidlyconnected to outlet 105. Casing part 103 defines port 106 and normallyopen port 108 which are, respectively, fluidly connected to inlet 107and outlet 109. Casing part 103 further defines an extension 110 whichhas a cylindrical chamber 112 formed therein as well as an annulargroove 114 and shoulder 116 formed on the exterior of the extension 110.A valve element 120 includes a flexible or pivotable blade 122 havingone end received in a complementary recess 123 formed in casing part 102so as to permit the locating and securing of valve element 120 in theassembling of casing parts 102 and 103. Blade 122 has a stiffener in theform of a stepped turned up flange 124 as well as yoke assembly 126 andlow reluctance ferro magnetic pad 128 secured thereto. As is best shownin FIGS. 7 and 8, blade 122 also has a necked down portion 125 whichdefines the point of flexure of blade 122. Yoke assembly 126 includes apolyurethane film disc 130 which alternatively seats on port 104 or port108 in a valving action. Because the yoke assembly 126 moves through anarc in moving between the positions blocking either port 104 or port108, it is necessary to have the film disc 130 become co-planar with theseating face of ports 104 and 108. To achieve this, yoke 131 is providedwith stepped diametrically extending pivot rods 132 as is best shown inFIGS. 8 and 9. Stepped pivot rods 132 are rotatably or pivotablyreceived in mounting holes 127 in stepped turned up flange 124. Filmdisc 130 is held in place in yoke 131 by ring 133 which is press fitinto yoke 131 with film disc 130 therebetween. Yoke 131 is thereforeable to pivot into a co-planar engagement with port 104 or 108 and ismoved to the co-planar engagement due to the unbalanced torsional forceon the yoke 131 when film disc 130 is not co-planar and engages only oneside thereof when engaging port 104 or 108. In installing yoke assembly126, one or both of the stepped turned up flanges 124 is bent towardsflat a sufficient amount to permit yoke assembly 126 to be snapped intomounting holes 127 and the flange(s) returned to their original shape.Screw 136 is threadably secured in casing part 103 and engages blade 122so as to provide a seating bias to cause film disc 130 to close port 104as illustrated in FIG. 5 in an unactuated position of actuator 150 or250. The necked down portion 125 of blade 122, as is best shown in FIGS.7 and 8, defines the pivot for flexure of blade 122 since it providesthe least resistance to flexure.

As best shown in FIG. 4, the valve assembly or proximity switch 100 issecured in place by inserting extension 110 into hole 141 in sheet metalmember 140 such that shoulder 116 engages sheet metal member 140.Typically, sheet metal member 140 is a member which may be installed inthe wall of a plenum. A C-clip 142 or other suitable attachment means isplaced in groove 114 and engages the opposite side of sheet metal member140 as that engaged by shoulder 116.

With valve assembly 100 secured in place in member 140, an actuator canthen be attached to member 140. Referring to FIG. 4, actuator 150includes a charged thermostatic bellows 152 which is preferably ofcopper and filled with gas. Magnetic actuator 164 is secured to bellows152 and carries a magnetic member 165 which is reciprocated in chamber112 by the expansion and contraction of bellows 152 due to changes inthe temperature of the warm or cool air stream to which it is exposed.Magnetic member 165 acts as a proximity switch with respect to magneticpad 128 in that magnetic member 165 is not exposed to the fluid withinthe chamber 129 but causes the movement of film disc 130 in a valvingaction by attracting magnetic pad 128 when in proximity thereto. InFIGS. 4 and 5 the structure of the valve assembly or proximity switch100 is identical but FIG. 4 illustrates the position of valve element120 due to the magnetic attraction between magnetic member 165 andmagnetic pad 128 whereas FIG. 5 illustrates the unactuated position ofvalve element 120 due solely to the biasing effect of screw 136. Theposition of bellows 152 and therefore magnetic member 165 can beadjusted by screw 190.

In FIG. 5, the valve assembly 100 is the same as that illustrated inFIGS. 3 and 4, but actuator 150 has been replaced with a differentthermal actuator 250. The thermal actuator 250 is specificallyillustrated as a phase change element 252 where a solid phase materialgoes to a liquid phase in the temperature range of interest and with anincrease in volume, but could be a bimetal. In the unactuated positionillustrated, compression spring 255 seats against stop 254 and capmember 256. Cap member 256 provides a seat for the head 258 of plunger260 and is biased in opposition to spring 255 by spring 262 which seatsagainst magnetic actuator 264 and head 258. Magnetic actuator 264carries a magnetic member 265 which is reciprocated in chamber 112 bythe actuator 250. The spring 262 serves as a lost motion device in thatit absorbs overtravel of head 258 after magnetic actuator 264 hasbottomed out in its movement within chamber 112. Spring 270 serves toreturn plunger 260 to the illustrated position when the output force isreduced in thermal element 252. The thermal element 252, located in thewarm or cool air stream, senses the flowing air temperature and acts bychanging phase, when appropriate. The position of thermal element 252and therefore magnetic member 265 can be adjusted by screw 290.

Referring now to FIG. 6, the valve assembly or proximity switch 100 isthe same as that of FIGS. 3-5 but actuator 350 includes an internalspring solenoid 352 for positioning valve element 120 in response to anelectric signal. The magnetic actuator 364 which carries magnetic member365 is attached to the shaft of the solenoid. Upon energizing of thesolenoid 352, magnetic member 365 is moved outwardly in chamber 112causing outlet port 104 to close, as illustrated. When the power isremoved from the solenoid 352 the internal spring (not illustrated)causes the magnetic actuator 364 to move magnetic member 365 furtherinto chamber 112 to thereby attract magnetic pad 128 causing valve disc130 to engage and close port 108 and to open port 104. Power to solenoid352 through contacts 353 is provided upon the closing of switch 180which can be a thermostatically responsive switch or a computercontrolled switch. The power source 300 can be any suitable source ofpower and may be incorporated into a computer control.

As noted, the valve assembly 100 is identical in FIGS. 3-6 FIGS. 5 and 6show valve element 120 in the same position closing port 104. However,FIG. 5 is a cold or an unactuated position of actuator 250 and FIG. 6 isan actuated position of actuator 350. The difference in designation isdue to the fact that energy in the form of heat is necessary toexpand/acutate the actuators 150 and 250 whereas electrical energy isnecessary to contact/actuate actuator 350. FIG. 4 shows the valveelement 120 in its actuated position closing port 108. In the case ofactuator 350, the solenoid 352 is actuated in response to the completingof an electric circuit by the closing of a switch 180 which may becaused by a computer or the like or may be a thermally actuated switchexposed to the conditioned air which completes the power supply circuitupon closing. Actuators 150 an 250, however, are responsive to thetemperature of their surroundings and would normally be exposed to theplenum air or the moving air stream.

Although preferred embodiments of the present invention have beenillustrated and described, other changes will occur to those skilled inthe art. It is, therefore, intended that the present invention is to belimited only by the scope of the appended claims.

What is claimed is:
 1. A changeover arrangement for a central airconditioning unit for selectively supplying either warm or cool aircomprising:means for supplying conditioned air; means for controllingthe flow of said conditioned air into an area; first bleed-typethermostatic means for regulating said means for controlling the flow soas to maintain a preset temperature when cool conditioned air is beingsupplied; second bleed-type thermostatic means for regulating said meansfor controlling the flow so as to maintain a preset temperature whenwarm conditioned air is being supplied; means for connecting said meansfor controlling the flow to said first thermostatic means when coolconditioned air is being supplied and to said second thermostatic meanswhen warm conditioned air is being supplied; said means for connectingincluding a valve comprising: housing means defining a chamber andhaving an inlet fluidly connected to said means for controlling and afirst and second outlet respectively connected to said first and secondthermostatic means and in fluid communication with said chamber; valveelement means including ferromagnetic means and pivotably mounted insaid chamber so as to be movable between a first position blocking oneof said outlets and a second position blocking the other of saidoutlets; biasing means for normally positioning said valve element meansin said first position; and actuator means including a magnetic memberand means for moving said magnetic member into and out of proximity withsaid ferromagnetic means whereby said valve element is caused to move tosaid second position due to magnetic attraction between saidferromagnetic means and said magnetic member when in proximity to causesaid one outlet and the associated one of said thermostatic means to befluidly connected to said means for controlling and returns to saidfirst position to cause said other outlet and the associated one of saidthermostatic means to be fluidly connected to said means for controllingwhen out of proximity.
 2. The valve of claim 1 wherein said means formoving includes thermostatically responsive means.
 3. The valve of claim1 wherein said means for moving includes a solenoid.
 4. The valve ofclaim 3 wherein said means for moving includes a thermostaticallyresponsive switch.
 5. The changeover arrangement of claim 1 wherein saidvalve element means further includes means for locating the flexurepoint of said valve element means.
 6. The changeover arrangement ofclaim 1 wherein said valve element means further includes a valve bladewith a valve disc pivotably mounted thereon so as to be co-planar withsaid first and second outlets when seated thereon.